The present invention relates to warheads for use in air defense missiles and, more particularly to improvements in fragmenting warheads whereby the on-target fragment density is significantly increased without increasing warhead mass.
Conventional missile warheads are annular in cross section. When the charge is fired the fragments are distributed with substantially uniform density radially outward from the longitudinal axis of the missile. Assuming that firing occurs at the optimum time during the missile-target encounter, the probability of a target being hit by a warhead fragment depends upon the mass of the warhead, the size of the target, and the distance between the missile and target. Referring to FIG. 1 by way of illustration, a target 1 having an eight foot cross-sectional diameter is shown in an encounter with a missile warhead 2 having an eight inch cross-sectional diameter. The maximum permissible spacing between target 1 and missile 2 at the moment of firing is assumed to be eighty feet. Imaginary lines A and B are drawn from the longitudinal axis of warhead 2 to the top and bottom, respectively, of target 1. The angle 2.alpha. subtended between lines A and B corresponds to the angular portion of warhead 2 from which fragments are directed toward the target. For the dimensions assumed in FIG. 1, angle 2.alpha. turns out to be 5.72.degree.. Since there are 360.degree. of fragmenting warhead surface, and the fragment density is uniform in all directions about the missile axis, the percentage of warhead fragments which hit target 1 is ##EQU1## This extremely small percentage considerably limits the target hit probability and therefore places considerable demands on the missile guidance system to bring the missile sufficiently close to the target to considerably increase hit angle 2.alpha.. Alternatively, a warhead of larger mass may be used to increase the number of warhead fragments and likewise increase the fragment density uniformly in all directions.
The problem of increasing the on-target fragment density without increasing warhead mass or guidance precision has been attacked with limited success in the prior art. The most significant approach has been the use of fragment mass focusing, a technique in which the location and/or the firing sequence of the charge is arranged to direct fragments in one direction to a greater extent than in other directions. Unfortunately, this results in only a slight improvement in on-target fragment density.
It is therefore an object of the present invention to significantly increase the hit probability for a warhead by increasing the fragment density at the target without increasing warhead size.
It is another object of the present invention to provide a warhead configuration which projects significantly higher fragment densities toward a target without increasing missile size.